1. Field of the Invention
The invention relates to a variable impedance circuit, more particularly to a variable impedance circuit which can be implemented entirely in a semiconductor chip.
2. Description of the Related Art
Variable impedance circuits are used in a variety of electronic circuits, such as filters and voltage-controlled oscillators. Since most of these electronic circuits have come to be incorporated in semiconductor chips as monolithic integrated circuits, it would be desirable to have a variable impedance circuit which can be made compatible with the integrated circuit, i.e. to be internal to the monolithic chip, so as to reduce the size and minimize the complexity of the electronic circuit.